Patent GB-320414-A (GB)
Title: Improvements in or relating to vehicle brake mechanism
IPC: F16D65/09
Filed: 1928-07-13
Abstract: 320,414. Clark, D'A. M., (Bendix Brake Co.). July 13, 1928. Blocks and shoes acting on drums; force-transmitting mechanism; compensating for wear.- Vehicle brake mechanism comprises brake shoes which are held in any position to which they are shifted so that the release position is determined by the wiping action of the drum. The shoes are held by friction means including a tensioned spring 126, Fig. 12 passing through transverse openings in the shoe 90 and connected to the brake backing plate 42 and a washer or crosspm 130 engaging the side of the shoe opposite the backing plate. The spring may be inclined to help take the weight of the shoe. Spring 136, too light to overcome the friction means may be provided between the shoes. Each wheel brake comprises two shoes connected by a floating and adjustable joint comprising a right and left-hand screw 94, Fig. 7, threaded into pivots 96 mounted in openings in the shoes and having locknuts 104 extending through openings in the end of the shoes and bearing against the pivots 96. The shoe is applied by a floating lever 106. operated by Bowden cable 36 and engaging one shoe directly and engaging a thrust projection 110 on the other shoe. The lever fits over an anchoring abutment on either side of which the brake shoes anchor according to the rotation of the brake drum. The abutment comprises a sleeve encircling roller bearings surrounding a fixed post 118. A stamping 122 held by a collar pin 120 through the post 118, confines the rollers against endwise movement and the lever 106 against lateral displacement. In another arrangement the lever is pivoted to an extension of the lower shoe and forked at its end to have .wedging engagement with pins extending from each side of the other shoe. The screw 94 is inclined at an angle in order to increase the servo action and to increase the pressure on the left hand end of the lower shoe. In another arrangement the adjustable joint between the shoes consists of two links joined together to form a knuckle engaging an adjustable eccentric. The brake applying lever is fulcrumed in the upper shoe and curved around the anchoring abutment to engage the other shoe. Another brake applying lever is forked and fulcrumed to an extension of the lower shoe and connected by links to the upper. The rear wheel brake levers are connected to either end of a cable passing over a pulley mounted between two plates between which is mounted another pulley over which passes another cable connected to two levers loosely mounted on a shaft. One of these levers is connected to the hand lever and the cable is connected to a cable passing over and under two pulleys mounted on the first pedal respectively above and below its fulcrum. The position of one pulley is adjustable. The other end of the cable 58, Fig. 3, is connected to an arm 76 swinging in a. horizontal axis on the front axle 22. The cable so operating the front brakes passes over the rounded base of the arm 76 and behind a pulley 82 at the outer end of the arm. Thus the foot pedal applies all four brakes and the hand lever the rear brakes only.